U S. Pat. No. 3,665,535, issued May 30, 1972, discloses a swim fin assembly including webs pivotally mounted on rigid frames extended forwardly from the feet of a user. The webs are pivoted intermediate their longitudinal ends. The extent of pivotal movement available to the webs in response to kicking action of the user is mechanically limited by interconnections between the supporting frames and the webs. The disclosure of U.S. Pat. No. 3,665,535 is hereby incorporated into the present disclosure by reference.
The present invention arose from continuing efforts to improve the efficiency and operation of the swim fin disclosed in U.S. Pat. No. 3,665,535. It continues to simulate the swimming action of sea mammals, but further incorporates a novel aerodynamic web shape that reduces turbulence created by the swim fin and improves its performance substantially.
According to the details of the web embodiment disclosed and shown in the accompanying drawings, the web is formed as a rigid member having a substantially transverse trailing edge intersecting a rearwardly curved leading edge that is generated as a swept-back ellipse. The desired elliptical curvature is maintained across the full width of the web, which has proportional longitudinal sections across its width having a constant maximum thickness to length ratio. This web produces the most forward thrust with the least amount of kicking effort.